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Mechanical and hydraulic properties of carbonate rock:the critical role of porosity

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第4期15卷 814-825页

作者： Kam ng J.Carlos Santamarina Department of Civil and Architectural Engineering and Construction Management University of WyomingLaramieWY82071USA Physical Science and Engineering Division King Abdullah University of Science and TechnologyThuwal23955-6900Saudi Arabia

Carbonate rocks are extensively used in civil infrastructure and play a critical role in geoenergy geoengineering,either as hydrocarbon reservoirs or potential repositories for CO_(2)geological *** genesis and diagenetic overprint determine the properties of carbonate *** study combines recent data gathered from Madison Limestone and an extensive dataset compiled from published sources to analyze the hydraulic and mechanical properties of limestone carbonate *** models and data analyses recognize the inherently granular genesis of carbonate rocks and explain the strong dependency of physical properties on *** asymptotically-correct power model in terms of(1-Ф/Ф*)a is a good approximation to global trends of unconfined stiffness E and unconfined compressive strength UCS,cohesive intercept in Mohr-Coulomb failure envelopes,and the brittle-toductile transition *** power model is the analytical solution for the mechanical properties of percolat.ng granular *** adopted a limit.ng granular porosityФ*=0.5 for all models,which was consistent with the loosest packing of monosize *** fitted power model has exponent(α=2)in agreement with percolation theory and highlights the sensitivity of mechanical properties to *** and models confirm a porosity-independent ratio between unconfined stiffness and strength,and the ratio follows a log-normal distribution with mean(E/UCS)≈*** high angle of internal shear strength measured for carbonate rocks reflects delayed contact failure with increased confinement,and it is not sensitive to *** spans more than six orders of *** size controls pore size and determines the reference permeability k^(*)at the limit.ng porosityФ*=*** a given grain size from fine to coarse-grained dominant carbonates,permeability is very sensitive to changes in porosity,suggest.ng preferential changes in the internal pore network during compaction.

关键词： Rock porosity Carbonate permeability Rock unconfined stiffness Unconfined compressive strength(UCS)

On Chiral Space Groups and Chiral Molecules

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Chinese Journal of Structural Chemistry 2003年第1期22卷 37-38页

作者： ng Seik Weng 胡盛志 Institute of Postgraduate Studies University of Malaya 50603 Kuala Lumpur Malaysia Department of Chemistry Xiamen University Xiamen 361005 China

this note explains the relationship (as well as the absence of a relationship) between chiral space groups and chiral molecules (which have absolute configurations). For a chiral molecule, which must crystallize in a chiral space group, the outcome of the absolute configuration determination must be linked to some other properties of the chiral crystal such as its optical activity for the observation to the relevant.

关键词：手性空间群手性分子手性化合物有机合成有机化合物晶体结构

Preconditioned Iterative Methods for Algebraic Systems from Multiplicative Half-Quadratic Regularization Image Restorations

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Numerical Mathematics(theory,Methods and Applications) 2010年第4期3卷 461-474页

作者： Michael K.ng Department of Mathematics Hong Kong Baptist UniversityKowloon TongHong Kong

Image restoration is often solved by minimizing an energy function consist.ng of a data-fidelity term and a regularization term.A regularized convex term can usually preserve the image edges well in the restored *** this paper,we consider a class of convex and edge-preserving regularization functions,i.e.,multiplicative half-quadratic regularizations,and we use the Newton method to solve the correspondingly reduced systems of nonlinear *** each Newton iterate,the preconditioned conjugate gradient method,incorporated with a constraint preconditioner,is employed to solve the structured Newton equation that has a symmetric positive definite coefficient matrix. the eigenvalue bounds of the preconditioned matrix are deliberately derived,which can be used to estimate the convergence speed of the preconditioned conjugate gradient *** use experimental results to demonstrate that this new approach is efficient, and the effect of image restoration is reasonably well.

关键词： Edge-preserving image restoration multiplicative half-quadratic regularization Newton method preconditioned conjugate gradient method constraint preconditioner eigenvalue bounds

Production of rhamnolipids-producing enzymes of Pseudomonas in E. coli and structural characterization

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Frontiers of Chemical Science and Engineering 2017年第1期11卷 133-138页

作者： Kata Kiss Wei t.ng ng Qingxin Li Institute of Chemical & Engineering Sciences Agency for Science Technology and Research Jurong Island 627833 Singapore

Rhamnolipids are a class ofbiosurfactants that have a great potential to be used in industries. Five proteins/enzymes, namely RhlA, RhlB, RhlC, RhlG and RhlI, are critical for the production of rhamnolipids in Pseudomonas aeruginosa. Four of the 5 proteins except RhlC were successfully over-expressed in E. coli and three of them （RhlA, RhlB and RhlI） were purified and obtained in milligram quantities. the purified proteins were shown to be folded in solution. Homology models were built for RhlA, RhlB and RhlI. these results lay a basis for further structural and functional characterization of these proteins in vitro to favor the construction of super strains for rhamnolipids production.

关键词： rhamnolipids Pseudomonas RhlA RhlB,RhlI protein folding

the effect of variable viscosity on the flow and heat transfer of a viscous Agwater and Cu-water nanofluids

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Journal of Hydrodynamics 2013年第1期25卷 1-9页

作者： VAJRAVELU Kuppalapalle PRASAD Kerehalli Vinayaka ng Chiu-On Department of Mathematics University of Central Florida Department of Mathematics VSK University Department of Mechanical Engineering The University of Hong Kong

A numerical study is carried out to study the effects of the temperature dependent viscosity on the flow and heat transfer of a nanofluid over a flat surface in the presence of viscous dissipation. the governing nonlinear partial differential equations are transformed into nonlinear ordinary differential equations, and are solved numerically by the Keller-box method. the numerical results indicate that the effect of nanoparticle volume fraction is to increase the heat transfer and hence enhance the thermal boundary layer thickness. this is true even in the presence of variable viscosity and the viscous dissipation. Furthermore, the results obtained for heat transfer characteristics with nanoparticles reveal many interest.ng behaviors that warrant further study on the effects of the ＂nano-solid-particles＂.

关键词： nanofluid particles variable viscosity boundary layers viscous dissipation Keller-box method

Measuring gravitational effect of superintense laser by spin-squeezed Bose-Einstein condensates interferometer

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Chinese Physics B 2022年第5期31卷 265-273页

作者： Eng Boon ng C.H.Raymond Ooi Department of Physics University of MalayaKuala Lumpur 50603Malaysia

We consider an extremely intense laser,enclosed by an atom *** gravitational potential generated from the high-intensity laser is solved from the Einstein field equation under the Newtonian *** compute the strength of the gravitational force and study the feasibility of measuring the force by the atom *** intense laser field from the laser pulse can induce a phase change in the interferometer with Bose-Einstein *** push up the sensitivity limit of the interferometer with Bose-Einstein condensates by spin-squeezing effect and determine the sensitivity gap for measuring the gravitational effect from intense laser by atom interferometer.

关键词： intense laser field atom interferometer Bose-Einstein condensates spin-squeezing

NUMERICAL SIMULAtION OF 3-D DENSE SOLID-LIQUID tWO-PHASE tURBULENt FLOW IN A NON-CLOGGIng MUD PUMP

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Chinese Journal of Mechanical Engineering 2004年第4期17卷 623-627页

作者： YuanShouqi ZhangPei~ng ZhangJinfeng XuWeixinq ResearchCenterofFluidMachine~Engineeringandtechnology JiangsuUniversityZhenjiang212013China

A mathematical model is set to evaluate the 3-D dense solid-liquid two-phaseturbulent flow in a non-clogging mud pump, the flow feature in the impeller channel is simulatedwith the tool of IPSA. Meanwhile, resort to tECPLOt as the post-processor, the simulation results isvisualized. the results show the main flow characteristics: there exists backflow and aberrantvelocities at inlet area and a relative velocity slip between two phases; A jet-wake flow pattern isdiscerned around the shroud-suction side area; the relative velocity vector of solid phase iscloser to the pressure surface than that of liquid phase and the trend is more obvious with theincrease of diameter; the kinetic energy of turbulence k and the dissipation rate e reach theirpeaks at the corner of pressure and suction surface. the simulation results show a good agreementwith the experimental flow features in the impeller channel, which prove the turbulent model used isvalid and provide a theoretical design basis to non-clogging pumps.

关键词： Non-clogging pump two-phase flow turbulent flow Numerical simulation

transdermal drug delivery systems in diabetes management: A review

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Asian Journal of Pharmaceutical Sciences 2020年第1期15卷 13-25页

作者： Li Ching ng Manish Gupta School of Pharmacy Monash University MalaysiaBandar Sunway 47500Malaysia Faculty of Pharmacy DIT UniversityDehradun 248009India

Diabetes mellitus is a chronic disease in which there is an insufficient production of insulin by the pancreas, or the insulin produced is unable to be utilized effectively by the body. Diabetes affects more than 415 million people globally and is estimated to strike about 642 million people in 2040. the WHO reported that diabetes will become the seventh biggest cause of mortality in 2030. Insulin injection and oral hypoglycemic agents remain the primary treatments in diabetes management. these often present with poor patient compliance. However, over the last decade, transdermal systems in diabetes management have gained increasing attention and emerged as a potential hope in diabetes management owing to the advantages that they offer as compared to invasive injection and oral dosage forms. this review presents the recent advances and developments in transdermal research to achieve better diabetes management. Different technologies and approaches have been explored and applied to the transdermal systems to optimize diabetes management. Studies have shown that these transdermal systems demonstrate higher bioavailability compared to oral administration due to the avoidance of first-pass hepatic metabolism and a sustained drug release pattern. Besides that, transdermal systems have the advantage of reducing dosing frequency as drugs are released at a predetermined rate and control blood glucose level over a prolonged time, contribut.ng to better patient compliance. In summary, the transdermal system is a field worth exploring due to its significant advantages over oral route in administration of antidiabetic drugs and biosensing of blood glucose level to ensure better clinical outcomes in diabetes management.

关键词： transdermal Diabetes Antidiabetic Insulin Drug delivery system

ON ALGORItHMS FOR AUtOMAtIC DEBLURRIng FROM A SIngLE IMAGE

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Journal of Computational Mathematics 2012年第1期30卷 80-100页

作者： Wei Wang Michael K.ng Department of Mathematics Tongji UniversityShanghai 200092China Centre for Mathematical Imaging and Vision and Department of Mathematics Hong Kong Baptist UniversityKowloon TongHong KongChina

In this paper, we study two variational blind deblurring models for a single linage,the first model is to use the total variation prior in both image and blur, while the second model is to use the flame based prior in both image and blur. the main contribution of this paper is to show how to employ the generalized cross validation （GCV） method efficiently and automatically to estimate the two regularization parameters associated with the priors in these two blind motion deblurring models. Our experimental results show that the visual quality of restored images by the proposed method is very good, and they are competitive with the tested exist.ng methods. We will also demonstrate the proposed method is also very efficient.

关键词： Blind deconvolution Iterative methods total variation Framelet Generalizedcross validation.